Sector ETFs that have reacted poorly to the no tapering news include regional bank and insurance funds, two sub-industries that had rallied as 10-year Treasury yields surged almost 41% from May 22 through Sept. 17.

David Blain, a financial adviser in New Bern, North Carolina, likes exchange-traded funds so much he’s put all his clients’ money in them. He also thinks individual investors trading ETFs on their own may be in for surprises when markets come under stress.